Apparatus for inspecting object surface

ABSTRACT

An apparatus for inspecting object surface according to an embodiment includes: an imaging device including an imaging area; an optical source; and a group of optical devices including a mirror and a lens, and causing a reflected light other than a regular reflection light from an object to be reflected by a mirror surface of the mirror, and to form an image in the imaging area of the imaging device through the lens, the regular reflection light being caused by a light incident to a surface of the object from the optical source, wherein the optical source, the mirror, the lens, and the imaging device are arranged in such a manner that the regular reflection light is not incident to the imaging area of the imaging device through the mirror and the lens.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2018-004536, filed on Jan. 15,2018, the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to apparatuses forinspecting object surface.

BACKGROUND

A surface inspection apparatus using magnetic characteristics or opticalcharacteristics is well known as an apparatus for inspecting an objectsurface without contact. The surface inspection apparatus using theoptical characteristics generally utilizes reflecting features ortransparent features. It is important to extract scattering lightincluding information of object surface nature when inspecting theobject surface by utilizing the optical features.

In a conventional surface inspection apparatus by utilizing the opticalfeatures, since a scattering light is mixed in a reflecting light fromthe object or a transparent light through the object, it is difficult toextract the scattering light and it is impossible to inspect the surfacenature of the object with high accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an apparatus for inspecting object surfaceaccording to a first embodiment.

FIG. 2 is a diagram showing an apparatus for inspecting object surfaceaccording to a second embodiment.

FIG. 3 is a diagram showing an example of a preferred arrangement of theapparatus for inspecting object surface according to the secondembodiment.

FIG. 4 is a diagram showing an apparatus for inspecting object surfaceaccording to a third embodiment.

FIG. 5 is a diagram showing an apparatus for inspecting object surfaceaccording to a fourth embodiment.

FIG. 6 is a diagram showing an apparatus for inspecting object surfaceaccording to a fifth embodiment.

FIG. 7 is a diagram showing an apparatus for inspecting object surfaceaccording to a sixth embodiment.

DETAILED DESCRIPTION

An apparatus for inspecting object surface according to an embodimentincludes: an imaging device including an imaging area; an opticalsource; and a group of optical devices including a mirror and a lens,and causing a reflected light other than a regular reflection light froman object to be reflected by a mirror surface of the mirror, and to forman image in the imaging area of the imaging device through the lens, theregular reflection light being caused by a light incident to a surfaceof the object from the optical source, wherein the optical source, themirror, the lens, and the imaging device are arranged in such a mannerthat the regular reflection light is not incident to the imaging area ofthe imaging device through the mirror and the lens.

The following is a description of embodiments of the present invention,with reference to the accompanying drawings.

First Embodiment

FIG. 1 is a diagram showing an apparatus for inspecting object surface(herein after also referred to as a surface inspection apparatus)according to a first embodiment. The surface inspection apparatus of thefirst embodiment is an apparatus for inspecting a surface of an object100, and includes an optical source 10, a mirror 30, a lens 60, animaging device 70, and an image processing device (herein after alsoreferred to as an image processor) 80. The optical source 10 is disposedat an end portion on a reflecting surface of the mirror 30.

The mirror 30 is disposed in such a manner that a mirror surface of themirror 30 is oblique to a center axis of the object 100. The opticalsource 10 is disposed at an end portion on the mirror surface of themirror 30 that is the nearest end portion to the object 100.

The lens 60 and the imaging device 70 are arranged in such a manner thatan optical axis of the lens 60 coincides with a central axis of animaging area (not shown) of the imaging device 70. The imaging area ofthe imaging device 70 includes photoelectric conversion elements thatare arranged in a matrix form and convert a light to an electricalsignal. The central axis of the imaging area means a line that passesthrough the center of the imaging area and is perpendicular to theimaging area.

The optical axis of the lens 60 intersects with a central axis of theobject 100. The central axis of the object 100 means a line connecting acenter of a first face to which a light is incident to a center of asecond face opposed to the first face. The optical axis of the lens 30is preferably arranged to be perpendicular to the central axis of theobject 100. The mirror 30 is preferably arranged in such a manner thatthe mirror surface of the mirror 30 is arranged to intersect with thecenter of the object 100 and the optical axis of the lens at an angle of45 degrees respectively.

A light emitted from the optical source 10 becomes a light 22 incidentto the object 100. After the light 22 is incident to the object 100, apart of the incident light 22 becomes a regular reflection light 24 by areflection law, another part of the incident light 22 becomes ascattering light 26 depending on surface condition of the object 100.The regular reflection light 24 is a reflection light having areflection angle that is equal to an incident angle of the incidentlight 22. The scattering light 26 is incident to the mirror surface ofthe mirror 30 and is reflected by the mirror surface. The light 27reflected by the mirror surface (not shown) forms an image in theimaging area of the imaging device 70 through the lens 60. The imageformed in the imaging area of the imaging device 70 is processed by theimage processor 80, and it is possible to inspect an aspect of thesurface condition of the object 100 and specify the object 100, andthereby obtaining the surface nature of the object 100. Duringinspecting, the object 100 may be fixed not to move, or may move along adirection perpendicular to the central axis of the object 100.

In the first embodiment, the optical source 10, the mirror 30, the lens60, and the imaging device 70 are arranged in such a manner that theregular reflection light 24 of the incident light 22 incident to theobject 100 from the optical source 10 is not incident to the imagingarea of the imaging device 70 through the mirror 30 and the lens 60. Inother words, the optical source 10, the mirror 30, the lens 60, and theimaging device 70 are arranged in such a manner that the regularreflection light 24 of the incident light 22 incident to an end portion100 a of the object 100 that is the nearest to the optical source 10 isnot incident to the imaging area of the imaging device 70 through themirror 30 and the lens 60.

In the first embodiment, a LED (Light-Emitting Diode) or the likes ispreferably used as the optical source 10. A light emitted from the LED,a fiber optical source, an electric light bulb, or a fluorescentmaterial and having various wave lengths may be used as the opticalsource 10. A CMOS (Complementary Metal-Oxide Semiconductor) sensor, aCCD (Charge-Coupled Device) or the likes may be used as the imagingdevice 70. And an imaging device that can detect the wavelength range ofthe optical source 10 may be used as the imaging device 70.

In the first embodiment, the optical source 10 is disposed at the endportion of the mirror surface of the mirror 30. If the regularreflection light 24 is not incident to the imaging area of the imagingdevice 70 through the mirror 30 and the lens 60, it is not necessarythat the optical source 10 is disposed at the end portion of the mirrorsurface of the mirror 30. In other words, it is not necessary that theoptical source 10 is in contact with the mirror surface of the mirror.

In the first embodiment, if the mirror 30 has one surface that is mirrorsurface and the mirror surface has a reflection features in which alight in a wavelength range of the optical source 10 can be reflected,the mirror surface may be a flat face or a concave face. In FIG. 1, themirror surface is a flat face.

As described above, according to the first embodiment, since the surfaceinspection apparatus is constituted in such a manner that the scatteringlight 26 from the object 100 is incident to the imaging area of theimaging device 70 through the mirror 30 and the lens 60, but the regularreflection light 24 is not incident to the imaging area of the imagingdevice 70 through the mirror and the lens 60, it is possible to inspectthe surface nature of the object 100 with accuracy.

Second Embodiment

FIG. 2 is a diagram showing an apparatus for inspecting object surface(herein after also referred to as a surface inspection apparatus)according to a second embodiment. The surface inspection apparatus ofthe second embodiment includes an optical source 10, a first mirror 32,a second mirror 34, a lens 60, an imaging device 70, and an imageprocessor 80.

In the second embodiment, the optical source 10 is faced to the object.Therefore, an optical axis of a light emitted from the optical axis 10is disposed to be parallel to a central axis of the object 100. Theoptical axis of a light emitted from the optical source 10 is alsoreferred to as an optical axis of the optical source 10.

The optical axis of the lens 60 is arranged to coincide with the centralaxis of the imaging area (not shown) of the imaging device 70. Theoptical axis of the lens 60 and the central axis of the imaging area ofthe imaging device 70 are arranged to intersect with the central axis ofthe object 100, preferably be perpendicular to the central axis of theobject 100.

The first mirror 32 is disposed between the optical source 10 and theobject 100, and disposed between the imaging device 70 and the secondmirror 34. The lens 60 is disposed between the imaging device 70 and thefirst mirror 32. The first mirror 32 is disposed to incline with respectto an optical axis of a light emitted from the optical source 10 and thecentral axis of the object 100 at a determined angle, for example, 45degrees. The first mirror 32 includes a first mirror surface faced tothe optical source 10 and a second mirror surface faced to the object100. The first mirror surface faced to the optical source 10 may be aflat face or a concave face. When the first mirror surface is a concaveface, for example, the concave face is a paraboloid, the optical source10 is preferably disposed to a focal position. In this case, light raysreflected by the paraboloid become parallel and is incident to thesecond mirror 34.

The second mirror 34 reflects a light reflected by the first mirrorsurface of the first mirror 32 and causes the light reflected by thesecond mirror 34 to be incident to the object 100. The second mirror 34is disposed to be inclined with respect to an optical axis of the lightemitted from the optical source 10 and the central axis of the object100 at determined angle.

The light 21 emitted from the optical source 10 is reflected by thefirst mirror surface of the first mirror 32, is incident to a mirrorsurface of the second mirror 34, and becomes an incident light 22 whichis reflected by the mirror surface of the second mirror 34 and incidentto the object 100. The incident light 22 is incident to the object 100,a part of the incident light 22 becomes a regular reflection light 24 bya reflection law, another part of the incident light 22 becomes ascattering light 26 depending on the surface condition of the object100. The regular reflection light 24 is a reflection light having areflection angle that is equal to an incident angle of the incidentlight 22. The scattering light 26 is incident to the second mirrorsurface of the first mirror 32 and is reflected by the second mirrorsurface. The light 27 reflected by the mirror surface (not shown) formsan image in the imaging area of the imaging device 70 through the lens60. The image formed in the imaging area of the imaging device 70 isprocessed by the image processor 80, and it is possible to obtain thesurface nature of the object 100.

In the second embodiment, in order to prevent a light emitted from theoptical source 10 from being directly incident to the imaging device 70,as shown in FIG. 3, let L be a distance between the optical source 10and a point at which the optical axis of the optical source 10intersects with the first mirror 32, and let 2l be a length of the firstmirror surface of the first mirror 32, the following relationalexpression is satisfied.

$L \leqq {\frac{}{\sqrt{2}}\{ {1 + \frac{1}{\tan ( {\sin^{- 1}{NA}} )}} \}}$

NA denotes a numerical aperture of the optical source, and satisfies theequation “NA=sin θ_(L)”. θ_(L) denotes the maximum angle that is anangle of a light beam incident to the first mirror surface of the firstmirror 32 from the optical source 10 with respect to the optical axis ofthe optical source 10 and is a maximum.

However, the intensity of the scattering light 26 detected by theimaging device 70 may be stronger than that of the regular reflectionlight 24 without satisfying above described expression. In this case,the image processor 80 conducts proper processes thereby performingfunctions for inspecting object surface.

A light emitted from the LED, a fiber optical source, an electric lightbulb, or a fluorescent material and having various wavelengths may beused as the optical source 10. For example, a CMOS sensor, a CCD or thelikes may be used as the imaging device 70. And an imaging device thatcan detect the light having the wavelength range of the optical source10 may be used as the imaging device 70.

In the second embodiment, the optical source 10, the first mirror 32,the second mirror 34, the lens 60, and the imaging device 70 arearranged in such a manner that the regular reflection light 24 of theincident light 22 incident to the object 100 from the optical source 10is not incident to the imaging area of the imaging device 70 through thesecond mirror surface of the first mirror 32 and the lens 60. In otherwords, the optical source 10, the first mirror 32, the second mirror 34,the lens 60, and the imaging device 70 are arranged in such a mannerthat the regular reflection light 24 of the incident light 22 incidentto an end portion 100 a of the object 100 that is the nearest to thesecond mirror 34 is not incident to the imaging area of the imagingdevice 70 through the second mirror surface of the first mirror 32 andthe lens 60.

As described above, according to the second embodiment, since thesurface inspection apparatus is constituted in such a manner that thescattering light 26 from the object 100 is incident to the imaging areaof the imaging device 70 through the second mirror surface of the firstmirror 32 and the lens 60, but the regular reflection light 24 is notincident to the imaging area of the imaging device 70 through the secondmirror surface of the first mirror 32 and the lens 60, it is possible toinspect the surface nature of the object 100 with accuracy.

Third Embodiment

FIG. 4 is a diagram showing an apparatus for inspecting object surface(herein after also referred to as a surface inspection apparatus)according to a third embodiment. The surface inspection apparatus of thethird embodiment has the same configuration as the surface inspectionapparatus of the second embodiment except that the disposition of theoptical source 10 and the dispositions of the lens 60 and the imagingdevice 70 are interchanged. Therefore, the disposition of the secondmirror 34 is different from that in the second embodiment. In otherwords, the optical axis of the lens 60 is arranged to coincide with thecentral axis of the imaging area (not shown) of the imaging device 70,and the optical axis of the lens 60 and the central axis of the imagingarea of the imaging device 70 are arranged to be parallel to the centralaxis of the object 100. The optical axis of the optical source 10, or acentral axis of a light emitted from the optical source 10 is arrangedto intersect with the optical axis of the lens 60 and the central axisof the imaging area of the imaging device 70, preferably intersect withthe optical axis of the lens 60 and the central axis of the imaging areaof the imaging device 70 at an angle of 90 degrees.

The first mirror 32 is disposed between the object 100 and the imagingdevice 70, and the lens 60 is disposed between the first mirror 32 andthe imaging device 70. The first mirror 32 is disposed to incline withrespect to the optical axis of the lens and the central axis of theimaging area of the imaging device 70, and also incline with the opticalaxis of the optical source 10. The first mirror 32 reflects a lightemitted from the optical source 10 and causes a light reflected by thefirst mirror 32 to be incident to the object 100.

The second mirror 34 is disposed in such a manner that the light emittedfrom the optical source 10 is reflected by the first mirror 32, becomesan light incident to the object 100, a scattering light 26 of the lightincident to the object 100 is reflected by the second mirror 34 andincident to the imaging area of the imaging device 70. Therefore, thesecond mirror 34 is disposed between the first mirror 32 and the lens60, and disposed on a side of the optical source 10 (an upper side withrespect to the central axis of the object 100 in FIG. 4) with respect tothe optical axis of the lens 60.

Next operations of the surface inspection apparatus according to thethird embodiment will be described.

A light emitted from the optical source 10 is reflected by the firstmirror 32 and is incident to the object 100. The imaging device 70 isdisposed in such a manner that most of the regular reflection light 24in the light reflected by the object 100 is reflected by the firstmirror 32, and is not incident to the imaging device 70. In particular,the imaging device 70 is faced to the object 100, and is disposed on aback side of the first mirror 32. A scattering light in the lightreflected by the object 100 is reflected by the second mirror 34 andforms an image in a imaging area (not shown) of the imaging device 70through the lens 60. The image formed by the imaging device 70 isprocessed by the image processor 80, thereby being able to inspect anaspect of the surface condition of the object 100 and specify the object100, and obtain the surface nature of the object 100. The object 100 isformed of material reflecting light, for example, paper, metal, cloth,or the likes.

As described above, according to the third embodiment, since the surfaceinspection apparatus is constituted in such a manner that the scatteringlight 26 from the object 100 is reflected by the second mirror 34 and isincident to the imaging area of the imaging device 70 through the lens60, but most of the regular reflection light 24 is reflected by thefirst mirror 32, it is possible to inspect the surface nature of theobject 100 with accuracy.

Fourth Embodiment

FIG. 5 is a diagram showing an apparatus for inspecting object surface(herein after also referred to as a surface inspection apparatus)according to a fourth embodiment. The surface inspection apparatus ofthe fourth embodiment is an apparatus for inspecting a surface of anobject 100, and includes an optical source 10, a partial transmissiondevice 41, a lens 42, a half mirror 43, a lens 44, a lens 45, a lens 46,a partial transmission device 48, an imaging device 70, and an imageprocessor 80.

The partial transmission device 41 has an aperture of which a radius isr₁ in a central portion, and is disposed to be separated from theoptical source 10 at a distance of d₁. The partial transmission device41 and the optical source 10 are disposed in such a manner that anoptical axis of a light emitted from the optical source 10 coincideswith a central axis through the aperture of the partial transmissiondevice 41. The lens 42 is disposed to separate from the partialtransmission device 41 at a focal length f₁ of the lens 42.

The lens 44 is disposed between the lens 45 and the lens 46, theirlenses 44, 45, 46 have a common optical axis. The optical axis of thelens 44, the lens 45, and the lens 46 intersect with the optical axis ofthe optical source 10. The optical axis of the lens 44, the lens 45, andthe lens 46 is preferably perpendicular to the optical axis of theoptical source 10. The optical axis of the lens 44, the lens 45, and thelens 46 is preferably disposed to coincide with the central axis of theobject 100 and the central axis of the imaging area (not shown) of theimaging device 70. The half mirror 43 is disposed between the lens 44and the lens 46, and a mirror surface of the half mirror 43 intersectswith the optical axis of the optical source 10 and the optical axis ofthe lens 44, the lens 45, and the lens 46. The half mirror 43 ispreferably disposed in such a manner that the mirror surface of the halfmirror 43 intersects with the optical axis of the optical source 10 andthe optical axis of the lens 44, the lens 45, and the lens 46 at anangle of 45 degrees respectively.

A focal length of the lens 44 is f₂, a focal length of the lens 45 isf₃, and a focal length of the lens 46 is f₄. The lens 44, the lens 45,and the lens 46 are disposed in such a manner that a distance betweenthe lens 44 and the lens 45 is equal to f₂+f₃, and a distance betweenthe lens 44 and the lens 46 is equal to f₂+f₄.

The imaging device 70 is disposed on one side of the lens 46 oppositefrom the lens 44. The partial transmission device 48 is disposed betweenthe lens 46 and the imaging device 70 and at a position where a distancefrom the lens 46 is equal to the focal length f₄. The partialtransmission device 48 has a structure in which a light interceptionportion having a disk shape of which a radius is r₄ is disposed in acentral portion. The partial transmission device 48 is disposed at aposition where a distance from the imaging area of the imaging device 70is equal to d₄.

A light emitted from the optical source 10 is narrowed by the apertureof the partial transmission device 41, and then collimated by the lens42. In other words, the partial transmission device 41 is disposed at afocal point of the lens 42. The light that is collimated by the lens 42is reflected by the half mirror 43, and conducted to the lens 44. Thelight passing through the lens 44 is incident to the object 100 throughthe lens 45. At that time, a telecentric optical system where a light isincident to a whole surface of the object 100 at the same incident angleoccurs. The regular reflection light 24 from the object 100 passesthrough the lens 45, the lens 44, and the half mirror 43, and is focusedby the lens 46. Since the partial transmission device 48 has the lightinterception portion at the central portion, the light is transmittedthrough an outer portion of the partial transmission device.

Depending on surface aspects of the object 100, the scattering light 26from the object 100 may be scattered in a specific direction differentfrom a direction in which the regular reflection light 24 transmits.Therefore, the scattering light 26 transmits through the partialtransmission device 48 and forms an image at the imaging area of theimaging device 70. The image obtained by the imaging device 70 isprocessed by the image processor, thereby being able to inspect thesurface of the object 100.

In the fourth embodiment, the partial transmission device 41 has atransmission portion of which a radius is r₄ at the central portion ofthe partial transmission device 41. The light interception portion ofthe partial transmission device 48 has a disk shape of which a radius isr₄, it is desirable to satisfy the following relationship. The lightpassing through the central portion of the partial transmission device41 is caused to form an image having a size of a radius r₀ at a positionof the focal length f₃ by the lens 45 as shown in FIG. 5. On a side ofthe optical source 10, an enlargement factor of the object 100 is f₁/f₂,a radius r₁ of the aperture of the partial transmission device 41 isequal to r₀×f₁/f₂. On a side of the imaging device 70, an enlargementfactor of the object 100 is f₄/f₂, a radius r₄ of the light interceptionportion of the partial transmission device 48 is equal to r₀×f₄/f₂.Therefore, the radii and the focal lengths of the partial transmissiondevice 41 and 48 are satisfied the following relational expression.

r₁: r₄=f₁: f₄

A light emitted from the LED, a fiber optical source, an electric lightbulb, or a fluorescent material and having various wavelengths may beused as the optical source 10. A CMOS (Complementary Metal-OxideSemiconductor) sensor, a CCD (Charge-Coupled Device) or the likes may beused as the imaging device 70. And an imaging device that can detect thelight having the wavelength range of the optical source 10 may be usedas the imaging device 70. The half mirror may have a shape of a flatplate or a cube.

As described above, according to the fourth embodiment, since thesurface inspection apparatus is constituted in such a manner that theregular reflection light 24 from the object 100 is emitted to the lightinterception portion of the partial transmission device 48 and a part ofthe scattering light 26 is emitted to portions other than the lightinterception portion of the partial transmission device 48, it ispossible that the scattering light is separated from the regularreflection light, thereby being able to inspect the surface nature ofthe object 100 with accuracy.

The scattering light may have large wavelength dependence. In this case,it is possible to effectively extract the scattering light by selectinga proper wavelength region in the imaging device.

Fifth Embodiment

FIG. 6 is a diagram showing an apparatus for inspecting object surface(herein after also referred to as a surface inspection apparatus)according to a fifth embodiment. The surface inspection apparatus of thefifth embodiment has the same configuration as the surface inspectionapparatus of the second embodiment shown in FIG. 2 except that the firstmirror 32 is replaced with a half mirror 32A.

In the fifth embodiment, a part of the light 21 emitted from the opticalsource 10 is reflected by the half mirror 32A, and incident to thesecond mirror 34. Another part of the light 21 emitted from the opticalsource 10 passes through the half mirror 32A and is incident to theobject 100. The light incident to the object 100 is reflected by theobject 100 and becomes the regular reflection light 25 and thescattering light 26. The scattering light 26 is incident to the imagingarea of the imaging device 70 through a mirror surface of the halfmirror 32A and the lens 60. A light incident to the second mirror 34 isreflected by the second mirror 34 and becomes a light 22 incident to theobject 100. A behavior of the light 22 is the same that described in thesecond embodiment.

As described above, like the second embodiment, in the fifth embodiment,since the surface inspection apparatus is constituted in such a mannerthat the scattering light 26 from the object 100 is incident to theimaging area of the imaging device 70 through the mirror surface of thehalf mirror 32A and the lens 60, but the regular reflection light 24 isnot incident to the imaging area of the imaging device 70 through themirror surface of the half mirror 32A and the lens 60, it is possible toinspect the surface nature of the object 100 with accuracy.

In the fifth embodiment, the half mirror 32A may be disposed to beperpendicular to the optical axis of the optical source 10. In thiscase, the second mirror 34 is discarded.

Sixth Embodiment

FIG. 7 is a diagram showing an apparatus for inspecting object surface(herein after also referred to as a surface inspection apparatus)according to a sixth embodiment. The surface inspection apparatus of thesixth embodiment has the same configuration as the surface inspectionapparatus of the second embodiment shown in FIG. 2 except that theobject 100 is disposed along a delivering path 150. In other words, theobject 100 is moved along the delivering path 150.

In the sixth embodiment, like the second embodiment, since the surfaceinspection apparatus is constituted in such a manner that the scatteringlight 26 from the object 100 is incident to the imaging area of theimaging device 70 through the second mirror surface of the first mirror32 and the lens 60, but the regular reflection light 24 is not incidentto the imaging area of the imaging device 70 through the second mirrorsurface of the first mirror 32 and the lens 60, it is possible toinspect the surface nature of the object 100 with accuracy.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel methods and systems describedherein may be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the methods andsystems described herein may be made without departing from the spiritof the inventions. The accompanying claims and their equivalents areintended to cover such forms or modifications as would fall within thescope and spirit of the inventions.

1. An apparatus for inspecting object surface comprising: an imagingdevice including an imaging area; an optical source; and a group ofoptical devices including a mirror and a lens, and causing a reflectedlight other than a regular reflection light from an object to bereflected by a mirror surface of the mirror, and to form an image in theimaging area of the imaging device through the lens, the regularreflection light being caused by a light incident to a surface of theobject from the optical source, wherein the optical source, the mirror,the lens, and the imaging device are arranged in such a manner that theregular reflection light is not incident to the imaging area of theimaging device through the mirror and the lens.
 2. The apparatusaccording to claim 1, wherein the optical source, the mirror, the lens,and the imaging device are arranged in such a manner that the regularreflection light caused by a light incident to an end portion of theobject that is the nearest portion from the optical source is notincident to the imaging area of the imaging device through the mirrorand the lens.
 3. The apparatus according to claim 1, wherein an opticalaxis of the lens intersects with a central axis of the object andcoincides with a central axis of the imaging device, a mirror surface ofthe mirror is inclined with respect to the central axis of the objectand the optical axis of the lens, and the optical source is disposed atan end portion of the mirror surface nearest to the object.
 4. Theapparatus according to claim 1, further comprising an image processorthat obtains a surface information of the object based on an imageformed by the imaging device.
 5. An apparatus for inspecting objectsurface comprising: an imaging device including an imaging area; anoptical source faced to a surface of an object to be inspected; a firstmirror including a first mirror surface and a second mirror surfaceopposed to the first mirror surface; a second mirror configured toreflect a light reflected by the first mirror and cause the lightreflected by the first mirror to be incident to a surface of the object;and a lens, wherein a reflected light other than a regular reflectionlight caused by a light incident to the surface of the object isreflected by the second mirror surface of the first mirror and forms animage in the imaging area of the imaging device through the lens, andthe optical source, the first mirror, the second mirror, the lens, andthe imaging device are arranged in such a manner that the regularreflection light is not incident to the imaging area of the imagingdevice through the second mirror surface of the first mirror and thelens.
 6. The apparatus according to claim 5, wherein an optical axis ofthe optical source is parallel to a central axis of the object, anoptical axis of the lens intersects with the optical axis of the opticalsource and coincides with a central axis of the imaging area of theimaging device, the first mirror surface is inclined with respect to theoptical axis of the optical source, and the second mirror surface isinclined with respect to the central axis of the object and the opticalaxis of the lens, and a mirror surface of the second mirror is inclinedwith respect to the optical axis and the optical axis of the lens. 7.The apparatus according to claim 5, wherein the following relationalexpression is satisfied, where L denotes a distance between the opticalsource and a point at which the optical axis intersects with the firstmirror surface of the first mirror, 2l denotes a length of the firstmirror surface of the first mirror, and NA denotes a numerical apertureof the optical source,$L \leqq {\frac{}{\sqrt{2}}{\{ {1 + \frac{1}{\tan ( {\sin^{- 1}{NA}} )}} \}.}}$8. The apparatus according to claim 5, wherein the first mirror is ahalf mirror.
 9. The apparatus according to claim 5, wherein the objectis moved along a delivering path.
 10. The apparatus according to claim5, further comprising an image processor that obtains a surfaceinformation of the object based on the image formed by the imagingdevice.
 11. An apparatus for inspecting object surface comprising: animaging device faced to a surface of an object to be inspected, andincluding an imaging area; an optical source; a first mirror configuredto reflect a light emitted from the optical source at a first mirrorsurface of the first mirror and cause the light reflected at the firstmirror to be incident to the surface of the object; a second mirrorconfigured to reflect a light at a second mirror surface of the secondmirror, the light being incident to the surface of the object andreflected by the surface of the object; and a lens, wherein the lightreflected by the second mirror surface of the second mirror is caused toform an image in an imaging area of the imaging device, the firstmirror, the second mirror, the lens, and the imaging device are arrangedin such a manner that a regular reflection light caused by a lightincident to the object is not incident to the imaging area of theimaging device through the second mirror and the lens.
 12. The apparatusaccording to claim 11, wherein the optical source is disposed so that anoptical axis of the optical source intersects with a central axis of theobject, the lens and the imaging device are disposed so that an opticalaxis of the lens coincides with a central axis of the imaging area ofthe imaging device, the first mirror is disposed so that the firstmirror surface is inclined with respect to the optical axis of theoptical source and the optical axis of the lens, and the second mirroris disposed so that a light other than a regular reflection lightreflected by the object is reflected at the second mirror surface. 13.The apparatus according to claim 11, further comprising an imageprocessor that obtains a surface information of the object based on animage formed by the imaging device. 14-17. (canceled)